Saturday, 13 December 2008

Leaking self bailers and anti-slip

No crew today, the wind low and the surf high... so no sailing. Also a very high tide. 61cm above chart datum in Port Said which is our standard port for the area. Yes, I know 61 cm high tide is absolutely nothing for most of the world, but for the eastern Med its a pretty high tide. In Larnaca sailing club the water was over the grill and up on the concrete of the launching ramp.

So with time to kill I set about trying to find why I get water coming in. I masked off the self-bailers with sellotape and then filled the bilges with water. No leak... till... it started coming through the sellotape on the port bailer. Then when the water came up to the level of the centre-board pin I started getting in from the centre-board case. Lifted the front so that the pin was out of the water and the leak stopped instantly.

That was excellent news. Basically it means the leaks are from the self-bailers and the centre-board pin. My fear had been there was a hidden crack at the stern of the centreboard case which would have been pretty well impossible to get to. Or... that my fibreglass repair to the centre-board case was not holding. Having seen [and hopefully fixed] the horrible bodge someone else had done to the centre-board case I was dreading that possibility. But no... just self-bailers and centre-board pin.

So why and how to fix? Last winter I had replaced the rubber seals on the self-bailers and when I had re-bedded the bailers into the hull I was not happy with the fix, and had then used silicone to 'seal' them in place. I thought silicone was the ideal sealant. Everyone I spoke to said that was what they used, except... Sue gave me Don Casey's Complete Illustrated Sailboat Maintenance Manual for my birthday this year and he had said that silicone was a fairly hopeless sealant [which is what I had now discovered myself] except under compression. Probably, had I bedded the self bailers into silicone, let the silicone cure and then at least 24 hours later tightened the nuts to compress the silicone it might have worked.

The centre-board pin was something others had suggested was where the leak was coming from but I had been not sure about. I suspect what has happened is that over the years the hole for the centre-board pin has worn and enlarged so that the pin itself is no longer a good seal. So how to fix it? I think I will make a washer for each side of the centreboard cased out of silicone. Then by compressing the washers with the nut on the pin, I should get it to seal. Silicone does reputedly seal quite well under compression, but it is not an adhesive seal and '...it should not be used below the waterline.' Apparently leaving it at least 24 hours to cure/go off before compression is the clue to an effective seal.

So on Don Casey's recommendation I went round the shops looking for polysulphide glue. All of them had either silicone or polyurethane. Polyurethane is apparently a very good adhesive seal, but permanent - like impossible if you ever wanted to change the self-bailers. Many of the glues had only Greek descriptions so I had to get assistants to translate. And sometimes they were not sure of the English so had to find other containers with both English and Greek on them to work out that the word was the Greek equivalent of polyurethane. Anyway I shall try during the week to find polysulphide and fix them later.

What I did get was a strip of aluminium for each end of the anti-slip. Tim had bought me a present of anti-slip tape from South Africa when he came back and although it adhered well to the thwart the ends looked ugly and one started to ride up. Not good news after only one month of doing the job. So, again at Tim's suggestion, I bought some aluminium strip which I have pop riveted to the thwart to both fix the ends down and give them a much smarter finish.

I also changed one of the twisted shackles for one of the mainsheet blocks. Last year I had bought two sizes of twisted shackle not knowing which would be right. The blocks were just too big for the small ones so I had used a big one. This meant the block was hanging about 2-3 cm lower than I wanted. So today I filed off the edge of the block to make it just slightly narrower and managed to fit one of the smaller twisted shackles which I then moused with the stainless steel wire I still have from the spring.